Sal M. Onella wrote:
"Hank Zoeller" wrote in message
...
Hello everyone,

I'm contemplating putting up a vertical antenna for HF use. I'm looking
at an approximate height of 30 feet or so. I am thinking of using
aluminum tubing (0.058" wall) in a 'telescoping' manner. Here are my
questions (so far):

1) Diameter. For wind resistance, should I start with something like 1
inch diameter and work down to 3/8 inch? Would the antenna be stronger
if I started with 2 inch diameter and worked down to 1-3/8 inch?

It would seem to me that the larger diameter might be better able to
withstand wind but it would also offer more resistance to wind possibly
negating the additional strength. But, I have no experience to draw
from. So, fat or slim?

2) I am planning a set of guy ropes at about the 12 foot level, a bit
over 1/3 height. Is there a better height for guy ropes? I can put as
much concrete in the ground as I like, and a very robust mount system is
possible. Is there any way to make an unguyed 30 footer that isn't a
tower form factor? Something like making the bottom 12 feet or so from
2 inch diameter, 1/4 inch wall tubing and then light weight tubing from
there up to full height?
--
73, Hank

http://www.valcom.ca/Guelph/products...b-u_photo.html This is
built for navy shipboard use so it may be "scary expensive." These are
virtually indestructible. You have to hit one with a crane boom to break
it. It is exactly what you described in your last paragraph. This size
whip covers 2 - 30 MHz with a tuner.

The Navy has used many 35-foot whips over the years. There were
five-section versions, but any you found now would probably be too corroded
to be of use.


Just look in the ARRL hanbook and use their 40 meter beam elements. They
self supporting and have a wind rating of 90mph. In a vertical
configuration with guys they would never blow down in a 100 years.

Dont forget the Navy Whips by valcom etc were designed to take a take
from a wave etc. Tons of water would bend any noodle. They really a
overkill. Some were also designed to take shock blasts from canons etc
and fatigue from 20,000 rounds weakening the metal.

Theres a lot of Yagi element stress element software around, i would use
it and design it to your spec. I would make sure you use 6061 which is
the most corrosion resistant and has the most strength. Array Solutions
sells element stress software from some Ham Kurt Andress or something
like that. ON4un also has some free software with his latest book.


How you gonna tune this beast on all bands? Would be interested to hear
how you going about this.


Pat